Answer:
0.2M NaOh
Explanation:
there are 0.2 mol of NaOH in 8.0 g. (8.0/40) =0.2. Molarity = mol/L = 0.2M.
Answer:
The correct option is the second option
Explanation:
Generally, the aim of science is to understand a particular concept in the best and the most correct way possible; hence experiments are done and repeated to ensure an explanation is actually true about a concept or need modification.
The atomic models have also been a "beneficiary" of this process. The different atomic models are usually been improved upon as scientists leaned more. For example, the Dalton's atomic theory has been modified to a more correct atomic description; some of which are shown below
(1) Dalton's theory suggested that an atom is the smallest unit of a molecule. We know now from different experiments (by J. J Thompson and Rutherford) that atoms are not the smallest molecules and are made up of smaller particles known as protons, neutrons and electrons.
(2) Dalton's theory suggested that atoms of the same elements are alike in all aspects. The knowledge of isotopy shows this is not always the case. As atoms of the same elements (isotopes) have the same atomic number but different mass number; hence cannot be said to be the same in all aspects.
(3) Dalton's theory also suggested that when atoms react, they do so in fixed, simple whole number ratio. The knowledge of organic chemistry shows atoms do not always react in simple whole number ratios
There are several modifications to different postulations by scientists that have also occurred aside from this, hence the most correct answer is that "As scientists learned more, they modified the atomic model"
the coefficients are equal is NOT a sign that a double displacement reaction has occurred
<u>Explanation:</u>
Usually during solutions of two ionic compounds are combined a precipitate (solid) is created. The mix may become cloudy, or may also separate, with the solids falling at the seat of the receptacle. Infrequently, the mix may bubble as a gas or water is produced.
A precipitation reaction is at two aqueous ionic compounds that make a unique ionic compound that is not soluble in water. The insoluble product compound is called the precipitate. The reaction, in this case, is not balanced, which are evaluated by summing coefficients.
Answer:
P = 0.0373 atm
Explanation:
Given data:
Mass of krypton = 1.86 g
Volume of krypton = 17.5 L
Temperature of krypton = 190 F
Pressure of krypton = ?
Solution:
First of all we will calculate the number of moles.
Number of moles = mass/ molar mass
Number of moles = 1.86 g/ 83.9 g/mol
Number of moles = 0.022 mol
Formula:
PV = nRT
P = nRT / V
P = 0.022 mol × 0.0821 atm. L. mol⁻¹. K⁻¹ × 360.928 K / 17.5 L
P = 0.652 atm. L /17.5 L
P = 0.0373 atm
For this, we use equations from the colligative properties of solutions specifically boiling point elevation and freezing point depression. The equations for these are expressed as:
ΔTb = kb m
where k is a boiling point elevation constant and m is the concentration in terms of molality
ΔTf = kf m
where k is a freezing point elevation <span>constant and m is the concentration in terms of molality
</span>
We use both expression to solve for the freezing point. For this case, concentration is the same. The equation will then be:
ΔTf = kf ( ΔTb / kb )
0-Tf = 1.86 (103.7 - 100 / 0.512 )
Tf = -13.4°C
